The good news about obesity is that recent trends suggest that its rate of increase in Americans has stabilized. The bad news is that many of us are already overweight or obese, and a significant part of the problem, as suggested by a recent study in The American Journal of Medicine, is a widespread decrease in physical activity.
Dr. U. Ladabaum and colleagues from the Stanford University School of Medicine compared data from the National Health and Nutrition Examination Surveys (NHANES) from 1988 1994,with data from surveys between 2009 2010. These are cross-sectional surveys conducted every two years, which involve physical measurements as well as dietary recalls and interviews about physical activity levels.
The researchers assessed BMI and waist circumference (an indicator of abdominal obesity), as well as physical activity and calorie intake. They found that the proportion of adult women (18-39 years of age) who reported no physical activity rose from 19 percent in the earlier survey to an astonishing 52 percent in 2009-2010. Such reports increased in adult men as well, but to a lesser extent from 11 percent to 44 percent.
Overall, over 50 percent of workforce-aged adults reported no leisure-time physical activity. This proportion was highest in black women aged 40-64 (71 percent), as well as in Mexican-American women aged 18-39 (57 percent), and black women aged 18-39 (60 percent).
In addition, the authors found that BMI and waist circumference increased in both women and men between the two study periods, and these increases were inversely associated with physical activity levels. For example, for adults reporting no leisure time physical activity, BMI increased by 8 percent in women and 2 percent in men.
ACSH s Dr. Ruth Kava commented, What I find most disturbing about these results is that many of the women who demonstrated great decrements in physical activity were in the prime years for child bearing. She continued, The fact that they also demonstrated increases in BMI and abdominal obesity does not bode well for them or their offspring. As Jane Brody points out in her column in today s New York Times, the babies of obese women have a higher risk of birth defects, and the mother is at greater risk of high blood pressure and gestational diabetes.